The invention relates to pet houses and more specifically relates to pet houses which allow a pet to enter and leave residence without assistance. The problem of litter box odors has received considerable attention and various approaches have been taken to reduce this problem for household pets such as cats. Chlorophyll containing litter box fillers have been used as has alfalfa-containing products for the purpose of reducing odors. Absorbant clays and various odor maskants have also found wide use but none of these approaches has solved the problem. In the past the only sure way of eliminating odor was to let the pet out of the house, but this is often impractical.